Assertion (A): The cells of sapwood take part in conduction of water and storage of food. Reason (R): During the growth process, the rings of sapwood gradually process and gradually convert into heartwood.

Select the correct option regarding the statements given above.

Correct answer. In older stems, the woody trunk is differentiated into two regions. The outer light coloured region is called sap wood or alburnum, and central dark coloured region is called heartwood or duramen. The cells of sapwood are living and functional. They take part in conduction of water and storage of food. The heartwood consists of dead cells. During the growth process, the rings of sapwood gradually process and convert into heartwood. The living cells of sapwood lose their protoplast and water content. The lumen of the xylem vessels gets blocked in growth of the parenchyma cells. Hence, both A and R are true.